Face in the clouds
Last August in New Brunswick, Canada, YouTube user "denisfarmer" shot a video of what may be the
most convincing "face in the clouds" ever. As a storm front moved across the sky, a man's profile seemed
to emerge.
Totally tubular
In February, a rare and beautiful "roll cloud" was photographed low in the sky above the Atlantic
Ocean near Brazil. Roll clouds are often born out of a storm's downdraft. Sinking cold air causes warm,
moist air near the ocean's surface to rise, and when the air reaches higher altitudes, the moisture in it
condenses to form a cloud. Winds from the storm then roll the cloud into a tube.
Heavenly halo
UFO believers took a strong interest in this strange cloud formation when it appeared over Moscow in
2009. But meteorologists identified the ring of light as an optical effect caused by sunlight hitting what
is known as a hole punch cloud. These appear as a circular or oval hole in a thin layer of air containing
supercooled water droplets. When a section of the layer is disturbed, such as by wind or a jet plane
passing through it, the droplets can freeze instantly or evaporate, leaving behind a hole.
Top hat in the sky
A cloud shaped like a top hat formed over Mount Fuji, Japan on June 21. Such formations, called
lenticular clouds, typically occur when moist air flows over a mountain and condenses.
Riding a volcano
Astronauts on board the International Space Station took this awesome photo of Sarychev volcano in Russia's Kuril Islands just at it started to erupt in 2009. The photo also captured some rather unusual atmospheric activity at the top of the
ash plume. According to NASA, the smooth white cloud atop the vigorously rising plume may be water condensation that resulted from rapid rising and
cooling of the air mass above the ash column, and is probably a transient feature. As for the surrounding
atmosphere, it has been shoved outward by the shock wave from the eruption.
Sky tsunamis
A series of huge breaking waves lined the horizon in Birmingham, Ala., last December, but they were
in the sky, not the ocean. The incredible cloud formations were pristine examples of "Kelvin-Helmholtz
waves," which develop when a fast-moving layer of fluid slides on top of a slower, thicker layer, dragging
its surface and causing crests of the thick layer to lurch forward.
Sky tsunamis
Another photo of tsunami-shape clouds that formed near Birminghal, Ala., in December.
Sky tsunamis
Another photo of tsunami-shape clouds that formed near Birminghal, Ala., in December.
Don't mess with Texas
This ominous cloud formation is the most severe type of thunderstorm: a supercell. It developed in May
in the Texas panhandle, and gave rise to at least one twister. "What you are seeing here is a well-developed
rotating supercell thunderstorm, and the condensation pattern at cloud base forms a 'belt' or 'wall'
appearance as air is lifted and sucked into the swirling storm," said Chris Walcek, a meteorologist at the
Atmospheric Sciences Research Center at the State University of New York, Albany.
Cloud lumps
These "mammatus clouds" were photographed in the city of Regina, Saskatchewan, in June 2012, following a severe storm warning and tornado watch. Although their formation is not completely understood, these rare clouds usually develop at the base of a thunderstorm, and appear lumpy because of instabilities and temperature differences between sinking and rising air.
